The invention concerns a delayed blowback firearm comprising a novel mechanism for reducing muzzle climb and attenuating recoil. The novel device resides forward of the bolt head and below the barrel and employs a mobile mass that reacts to firing in a manner to counteract recoil and muzzle jump forces in order to improve the handling and control of the firearm in use. Automatic and semi-automatic firearms, rifles, and pistols, can be fitted with the novel mechanism.
For some time there have been a number of mechanical systems available that are based on the principle of delayed blowback. All of them have been adapted for light automatic and/or semi-automatic firearms. These systems can be classified in three main categories and one sub-category, which are:    a) The delayed blowback of the bolt by inertia, known as the blowback bolt. In this case, the delayed blowback effect is generated solely by the weight of the mobile bolt and the force of a spring.    b) The delayed blowback of the bolt by means of a lever, slope and/or use of gas. Apart from those that use gas, these more complicated systems are paradoxically as old as automatic firearms with blowback bolts. Their advantage lies in better control of forces and a significant reduction in the weight and volume of firearms designed and built using these systems.    c) Delayed bolt blowback using a braking system. This last category will not be covered since it was abandoned long ago by the gunsmithing industry.
In the majority of cases, and with regards to the second category of systems, the mechanism for delayed blowback generally consists of three to five mobile parts, the only exception being for the sub-category of firearms using the principle of gas delayed blowback devices that use only a single mobile part (the functioning principle of Volkssturmgewehr). This last system is however rarely used and represents a very small share of global production of automatic pistols.
All these systems with delayed blowback each have the drawbacks inherent at the time of their conception, the end of the 19th and beginning of the 20th century. At this period, the chemistry of smokeless powder was still in its early stages. Combustion time and gas volume (hence pressure) generated by these powders imposed specific mechanical solutions relative to the state of metallurgy of the time. At the dawn of the 21st century, while the science and technology of powders and explosives have continued to evolve, we still use the same mechanisms, practically unchanged, which have now become totally unsuitable for these modern powders.
The simple blowback bolt has long been used to good advantage to design simple, easy-to-use, often low-cost automatic firearms. However, this particular system is suitable only for the use of relatively low power ammunition, as used by hand guns. Even with this kind of ammunition, the gun needs to have a heavy bolt to ensure that the projectile maintains acceptable ballistic characteristics. The need to use relatively heavy bolts imposes minimum volumes and dimensions that make the firearm heavy and cumbersome compared to the power of ammunition used. A few, rare automatic pistols have been designed and produced incorporating this first system, but the volume and weight constraints call for a powerful spring to compensate for reduced bolt weight, making the gun particularly difficult to handle. If this configuration is perfect for the design of small caliber automatic pistols (6.35 mm, 7.65 mm) it reaches its limits with the world's most commonly used ammunition for handguns, the 9 mm Parabellum. It is unusable for another major handgun caliber, the famous 11.43 mm or .45 calibers. As history confirms, no pistol functioning according to the blowback bolt principle has ever been produced for this ammunition.
The second category of delayed blowback systems uses an amplification lever, oblique helicoidal ramps or other slopes—the list is not exhaustive since there are so many variants. All these systems have a prime objective: to create a mechanical demultiplier of opposable force to that generated by the explosion of the powder charge contained in the cartridge. The second objective, consequence of the first, is to reduce the weight and volume of the total mass of the mobile unit that comprises the bolt. But a demultiplication effect becomes inversely overdrive, since the mobile unit of the gun is lighter so that it moves at a speed corresponding to overdrive ratio during the firing of the shot. This ratio is effectively variable but generally oscillates between 1:3 and 1:4 in function of the ammunition used (this system can be used for all types of ammunition). In consequence, the mobile unit paradoxically ends its movement in the receiver with energy that is much greater than the single mass of a blowback bolt. If, in the case of a machine gun pistol or heavier firearm, this energy can be dissipated by some kind of shock-absorbing device, or simply by a longer movement of the whole ensemble, these options are not available in an automatic pistol where the total passage of this mobile unit or bolt is mechanically and physically limited. The consequence of this short space is an abrupt stop of the mobile unit at the end of its course while its energy is still considerable. This provokes recoil and muzzle jump of the firearm that are prejudicial to its control and precision. This phenomenon is common to all automatic pistols, without exception, notably those functioning according to the principle of short recoil and barrel tilt wrongly referred to as the ‘Browning system’ which represents nearly 80% of global production of automatic pistols.
In all cases, and whichever of the systems described above is employed, in mechanical terms, they no longer meet the advantages offered by modern ammunition.